1. Field of the Invention:
The present invention relates to a process for treating metallic substrates so as to make them corrosion resistant. The invention also relates to metallic substrates which are prepared by this process.
2. Brief Description of the Prior Art:
It is known in the art to prepare corrosion-resistant substrates by applying thereto compositions comprising certain metallic ions. Eminent in the art are phosphatizing treating compositions. Examples of the phosphatizing treating compositions are those containing iron phosphate, zinc phosphate or zinc calcium phosphate.
Although the metallic treating compositions are, largely, employed on many industrial lines, they, nonetheless, have certain shortcomings. They are expensive; besides the cost of the chemicals, a considerable capital investment is required for equipment. Also, the process for using these treating compositions results in pollution, the cleaning of which adds to the overall cost of operations.
Co-filed application Ser. No. 347,845 describes novel compositions of tannin-epoxy reaction products which provide relatively inexpensive yet highly effective means of producing corrosion-resistant substrates. This invention provides an improved process for pretreating substrates, electrophoretically, with an improved corrosion resistance benefit inurring to the treated substrates.